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'Gaming routers' is pretty much just a branding thing.

Ultimately best performance will be a decent 'prosumer' router that can traffic shape (e.g. implement CAKE) in order to keep ping times down even when the link is under load and then good switching and wifi for the internal side of things (modern wifi standards, gigabit(+) ports).

opnsense would be fine for the former (as would OpenWRT on a pi4, say), and then you need to plug in some decent access points like tp-link eapxxx range or unifi, ruijie etc. That combo should outperform one of those gaming routers that look like an upside down robot spider thing. Well, it won't be worse and it'll be more fliexible at the very least.

Also remember that your dad's gaming device should be hardwired for best performance no matter what you end up going with.

Really this is more a /r/homenetworking thing, they'll have plenty of advice for you to, inc. hardware recs.

I don’t know for certain but I don’t think running your own router will decrease internet speed by much if at all, I’ve never done any testing to support wether it does or not, but I went from using Xfinitys modem/router getting 800up/25down to using a unifi udm pro, and I can say I consistently get the same speeds, I just get more control of everything that happens on my network. In my opinion switching to any router of your own would be best no matter what.

Also as a side note if he isn’t playing on Ethernet, I greatly doubt that the internet speed over WiFi will be affected at all if internet speed does drop at all from the router swap!

Can you run your own network downstream the gaming router?

Double nat so you have your own stuff running behind your security stuff which is behind the main router your stepdad uses.

He gets his priority routing and you get your security stuff

Most gaming is really low bandwidth, latency will be the big issue and an opnsense box will make very little, if any, difference in latency. You could have a 10mb connection with 10ms latency and it would be a better gaming experience than a 100Gb connection with 100ms latency.

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